Automatic change speed gearing



Sept. 29, 1936. w. c. HARRIS AUTOMATIC CHANGE SPEED GEARING Filed Oct.1l, 1934 l lli/lllll/1111111111111111111111111 I `Waltewr` C Harris b9j# HIS Attorney.

. Patented Sept.. 29, 19036 PATENT OFFICE AUTOMATIC CHANGE SPEED GEARINGWalter C..Harris, Erie, Pa., assignor to General Electric Company, acorporation of New York Application October 11, v1934.. Serial No.747,90d s claims. (ci. x4- 336) My invention relates to drivingarrangements for operating refrigerating apparatus or other machinerycarried by a vehicle.

It is often desirable to drive apparatus from a variable speed source ofpower, such as the engine or driving shaft of the vehicle to supplypower to a motor-generator set, refrigerating apparatus or otheradditional equipment mounted on the vehicle, which should preferably beoperated within l0 a small range of speed. Since the vehicle engine ordrive shaft system is subject to wide variations in speed, it isdesirable that some arrangement be provided so that the refrigeratingapparatus or the like will not be subject to the same variation l5 inspeed.

An object of my invention is to provide a vehicle having an improvedarrangement for establishing a driving connection between the vehicle Aengine or drive shaft system or the like and appa- `r`atus carried bythe vehicle which will drive the apparatus with a small variation inspeed.

Further objects and advantages of my invention will become apparent asthe following description proceeds, and the features of novelty which vlcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

In the accompanying drawing, Fig. 1 is a side elevation of a. portion ofa motor truck, partly in section, provided with a refrigeratingapparatus having a driving arrangement embodying my invention, and Fig.2 is an enlarged sectional yview of the speed-changing mechanismassociated with the driving arrangement shown in Fig. 1.

Referring to the drawing, in Fig. 1, I have shown my invention inconnection with a motor truck Vhaving an internal combustion engine I0provided with a clutch and fiywheel housingII and having aspeed-changing gear transmission I2 for connecting the engine to drivethe rear wheels ofthe truck through a drive shaft I3. The Seartransmission I2 includes a main drive shaft I 4 directly driven by theengine I0 through the clutch, and which drives a countershaft I5 15through gears I6 and II. A gear shifting lever I8 is arranged to slidegears I9, 20, and 2I mountled on a drive shaft Isa into engagement withgears 22, 23, and 24, respectively, on the countershaft I5 to obtain thefirst, second, and third` speeds respectively of the truck. The shaftI3a n is coupled to the drive shaft I3, Vbut is separate from the shaftI 4.v The fourth or high speed of the truck is obtained by shifting thelever I8 to .55 slide the gear 2I"over a gear 26 which is directlydriven by the shaft I4 and meshes with an internal gear formed withinthe gear 2i. In the construction illustrated, the engine i0 .is

arranged to drive an alternating-current generator 21 in order to supplycurrent for operating 5 a motor 28 which drives a refrigeratingcompressor 29. The generator 21 is provided with a y direct-currentexciter 30 for supplying the field current of the generator. In order tomaintain proper operation of the refrigerating machine it l0 isdesirable that the generator be arranged to supply power at all timeswhether the truck be moving or not. The generatorfl is, therefore,connected to be driven continuously while the engine is running providedthe clutch is engaged. lli 'I'he connection between the engine It andthegenerator 21 comprises. a power take-olf or countershaft 3lhaving a gear32 at the forward end thereof which continually meshes with the gear l1on the countershaft I5. The shaft 3l is '20 connectedvto drive thegenerator 21 through a pulley 33. a belt 3d, and a pulley 35 secured toa shaft 36. In the operation of the vehicle the engine speed, andtherefore the speed of the shaft 3l and the generator 21 driven therebywill be 25 subject to a wide variation. a

I reduce the variation in speed of the generator 21, which suppliespower to the refrigerating apparatus, by providing a centrifugallycontrolled speed-changing mechanism arranged between the 30 pulley 35and the driven shaft 4G of generator 21 which provides a high ratio ofdrive when the engine is running at low speed, and a lower ratio ofdrive when the engine is running at high speed. In this way thegenerator 21 is run with 35 a small variation of speed over a wide rangeof variation of engine speed. This speed changing mechanism includes anormally engaged clutch 31 which completes a high ratio drivingconnection between the drive shaft 38 on which the pul- 40 ley 35 isfixed, and a gear 38 fixed to a sleeve 38a. The sleeve 38a is rotatablysupported by bearings 38h between the sleeve 38a and the shaft 33 and bya bearing 30e between the sleeve and the housing 38;* of the speedchanging mechanism. The 45 clutch 31 comprises discs 38d splined on thesleeve 38a and discs 36e splined on a sleeve 40h which is fixed to theshaft 36. A spring 39 arranged in compression between a sleeve 40 fixedto the shaft 38 and a cup 40a bearing on a slidable housing 4I, 50forces the housing III against the discs 38e and holds the discs 38e and38d in driving engagement. When the clutch 31 is engaged as abovedescribed. power is transmitted from the shaft 36 and gear 38 to thegenerator 21 through. a gear 43 secured 55 to a counter shaft 42journaled in the housing 36j', a gear 44 secured to the other end ofcounter shaft 42, and a gear 45 secured to a sleeve 41a. fixed to thegenerator or auxiliary drive shaft 46. A bearing 41h between sleeve 40and the sleeve 41a permits a relative rotation between sleeves 40 and41a and a bearing 41e permits relative rotation between the sleeve 41aand the housing 361. During low-speed operation of the erigine, such aswould occur when the engine was operated at idling speed, or whenthe'vehicle was operated at low speed, the driving connection justdescribed drives the generator at a higher speed than the engine. Thisdriving connection would not be suitable at high engine speeds.

In order to establish a lower-speed driving connection between theengine l0 and the generator 21 when the engine speed increases, Iprovide a clutch 41 between the sleeve 40 flxed'to the shaft 36 and thegenerator shaft 46 which is adapted to complete a direct drivingconnection between these shafts. The clutch 31 is normally engaged andthe clutch 41 is arranged so that it is disengaged when the clutch 31 isengaged; The clutch 41 comprises discs 41d splined to the sleeve 41a anddiscs 41e splined to the sleeve 40. To engage the clutch 41, I provide acentrifugal device driven by the engine drivenshaft 36 which comprises aplurality of balls 48 arranged between an inclined surface on theslidable housing 4I and an inclined collar bolted to the sleeve 40h.Under the action of centrifugal force, the balls 46 move outwardly andcooperate with the inclined collar 49 andthe inclined surface of housing4I to move the housing 4I to the left against the discs 41d inopposition to the force exerted by the spring 39. This movement of thehousing 4I causes the discs 36d and 36e of the clutch 31 to becomedisengaged and causes the discs 41d and 41e of the clutch 41 to becomeengaged. This action completes a direct driving connection between theshaft 36 and the generator shaft 46 through the clutch 41, and at thesame time disconnects the higher ratio driving vconnection between theshaft 31 and the generator shaft 46 through the counter shaft 42.

In the operation of the vehicle, power is transmitted from the engine I0to the shaft 36 of the need-changing mechanism through a counter aft 3|driven by the engine and through a belt' 4 which runs on the pulley 33connected to the shaft 3| and the pulley 35 connected to the shaft 36.When the engine is running at idling speed or at low speeds, the clutch31 is engaged and the clutch 41 disengaged. The clutch 31 completes adriving connection from the shaft 36 through gears 36 and 43 to thecounter shaft 42 and from the counter shaft 42 tothe shaft 46 of thegenerator through gears 44 and 45. 'I'his driving connection rotates thegenerator shaft 46 at a higher speed than lthe shaft 36. As the enginespeed increases, the speed of shaft 36 which is driven :directly fromthe engine also increases. When the speed of shaft 36 reachesapredetermined value which corresponds to a particular engine speed theballs 46 move outwardly and slide the sleeve 4I to the left, disengagingthe discs 36d and 38e of the clutch 31 and engage the discs 41d and 41eof vthe clutch 41. The engagement of the clutch 41 completes a drivingconnection from the shaft 36 directly to the shaft 46 of the generator21 so that these shafts now rotate at the same speed. Itis apparent thatduring the operation of the vehicle, the generator shaft 46 is subjectto a smaller variation in speed than the shaft 36 which lis drivendirectly from the engine.

Although I have shown a particular embodiment of my invention, I do notdesire to be limited to the particular construction disclosed, and Iintend in the appended claims to cover all modifications which do notdepart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A power transmission including a drive shaft, a driven shaft, meansincluding a normally engaged clutch having a sleeve provided with aninclined collar mounted on said drive shaft for providing a drivingconnection between said drive shaft and said driven shaft, a slidablehousing having an inclined surface, a spring arranged'to urge saidinclined surface toward said inclined collar, means including a normallydisengaged clutch for establishing a driving connection between saiddrive shaft and said driven shaft of lower ratio than said firstmentioned driving connection therebetween, and means including aplurality of centrifugal weights re-` tained between said inclinedcollar and said inclined surface and arranged to urge said inclinedsurface away from said inclined collar under the shaft, a driven shaft,means including a normally engaged clutch having a sleeve provided withan inclined collar mounted on said drive shaft and a counter shaft forproviding a driving connection between said drive shaft and said drivenshaft, a slidable housing having an inclined surface and arranged toengage said normally engaged clutch, a spring arranged to urge saidinclined surface toward said inclined collar, means including a normallydisengaged clutch for establishing a driving connection between'saiddrive shaft and said driven shaft of lower ratio than said firstmentioned driving connection therebetween, and means including acentrifugal weight arranged between said inclined collar and saidinclined surface and adapted to urge said inclined surface away fromsaid inclined collar under the action of centrifugal force fordisengaging said normally engaged clutch and for engaging said normallydisengaged clutch.

3. A power transmission including a drive shaft, a driven shaft, acounter shaft, means including a normally engaged clutch having a sleeverotatably mounted on said drive shaft and connected to said countershaft and a sleeve pro- 4vided with an inclined collar for providing adrivmally disengaged clutch for establishing a driving connectionbetween said drive shaft and said driven shaft of lower ratio than saidrst named driving connection therebetween, and means including aplurality of centrifugal weights retained between said inclined collarand said inclined surface of said slidable housing arranged to urge saidinclined surface away from said inclined collar under the action ofcentrifugal force for disengaging said normally engaged clutch and forengaging said normally disengaged clutch.

WALTER C. HARRIS.

